Reactor for electrochemically processing a microelectronic workpiece including improved electrode assembly

ABSTRACT

A reactor assembly for electrochemically processing a microelectronic workpiece is set forth. The reactor assembly includes a processing bowl having one or more fluid inlets through which a flow of processing fluid is received. An electrode assembly is located within the process bowl in a fluid flow path of the fluid provided through the one or more fluid inlets. The electrode assembly includes a mesh electrode and a diffuser disposed in the fluid flow path prior to the mesh electrode to tailor the flow of processing fluid received from the one or more fluid inlets through the mesh electrode in a predetermined manner.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not Applicable

BACKGROUND OF THE INVENTION

[0003] The present invention is directed to an apparatus forelectrochemically processing a microelectronic workpiece. Moreparticularly, the present invention is directed to a reactor assemblyfor electrochemically depositing, electrochemically removing and/orelectrochemically altering the characteristics of a thin film material,like a metal or dielectric, at the surface of a microelectronicworkpiece, such as a semiconductor water.

[0004] For purposes of the present application, a microelectronicworkpiece is defined to include a workpiece formed from a substrate uponwhich microelectronic circuits or components, data storage elements orlayers, and/or micro-mechanical elements are formed.

[0005] Production of semiconductor integrated circuits and othermicroelectronic devices from microelectronic workpieces, such assemiconductor wafers, typically requires the formation and/orelectrochemical processing of one or more thin film layers on theworkpiece. Electroplating and other electrochemical processes, such aselectropolishing, electro-etching, anodization, etc., have becomeimportant in the production of semiconductor integrated circuits andother microelectronic devices from such workpieces. For example,electroplating is often used in the formation of one or more metallayers on the workpiece. These metal layers are typically used toelectrically interconnect the various devices of the integrated circuit.Further, the structures formed from the metal layers may constitutemicroelectronic devices such as read/write heads, etc. Suchelectrochemical processing techniques can be used in the depositionand/or alteration of blanket metal layers, blanket dielectric layers,patterned metal layers, and patterned dielectric layers.

[0006] The microelectronic manufacturing industry has applied a widerange of thin film layer materials to form such microelectronicstructures. These thin film materials include metals and metal alloyssuch as, for example, nickel, tungsten, tantalum, solder, platinum,copper, copper-zinc, etc., as well as dielectric materials, such asmetal oxides, semiconductor oxides, and perovskite materials.

[0007] Although the following discussion and subsequent embodiment ofthe present invention is described in the context of electroplating, itwill be recognized that the teachings herein can be extended to otherelectrochemical processing techniques in which at least two electrodesare used. To this end, the electroplating of a microelectronic workpiecegenerally takes place in a reactor assembly. In such a reactor assembly,an anode electrode is disposed in a plating bath, and the workpiece withthe seed layer thereon is used as a cathode. Only a lower face of theworkpiece contacts the surface of the plating bath. The workpiece isheld by a support system that may also include electrically conductivemembers that provide the requisite electroplating power (e.g., cathodecurrent) to the workpiece.

[0008] Generally stated, electrochemical processing occurs as a resultof an electrochemical reaction that takes place at the surface of theworkpiece. In electroplating, for example, atoms of the material to beplated are deposited onto the workpiece, which functions as a cathode,by introducing an external electrical power source that supplieselectrons to attract positively charged ions. The atoms are formed fromions present in the plating bath. In order to sustain the reaction, theions in the plating bath must be replenished. Such replenishment mayinclude the use of a consumable anode that releases the desired bathspecies as it is depleted from the bath.

[0009] When electroplating copper onto a workpiece, replenishment of thecopper ions in the plating bath may be accomplished, at least in part,through the use of a consumable phosphorized copper anode. As copperions are depleted from the plating bath, a corresponding number ofcopper ions are released by the anode into the plating bath. Otherchemicals that are depleted during the electroplating process may bereplenished by controlled dosing of the bath with one or more bathadditives.

[0010] As the thin film layer is deposited onto the cathode, a relatedelectrochemical oxidation reaction takes place at the anode. During thisrelated electrochemical reaction, byproducts from the electrochemicalreaction, such as particulates, precipitates, gas bubbles, etc., may beformed at the surface of the anode. Such byproducts may contaminate theprocessing bath and interfere with the formation of the thin-film layerat the surface of the workpiece. Furthermore, if these byproducts areallowed to remain in the plating bath at elevated levels near the anode,they may affect electrical current flow during the plating processand/or affect further reactions that take place at the anode. Stillfurther, if the byproducts are allowed to migrate proximate themicroelectronic workpiece, the byproducts could similarly interfere withthe desired deposition of electroplated material thereby affecting theuniformity of the thickness of the deposited material.

[0011] Such byproducts can be particularly problematic in thoseinstances in which the anode is consumable. For example, when copper iselectroplated onto a workpiece using a consumable phosphorized copperanode, a black anode film is produced. The presence and consistency ofthe black film is important to ensure uniform anode erosion. Thisoxide/salt film is fragile, however. As such, it is possible to dislodgeparticulates from this black film into the electroplating solution.These particulates can then potentially be incorporated into thedeposited film with undesired consequences.

[0012] A further consideration with respect to processes that use aconsumable anode is erosion of the anode. Specifically, as the anodeerodes, the distance between the anode and the cathode graduallyincreases. Furthermore, the overall shape of the anode as viewed by theworkpiece changes. Such erosion, in turn, affects the strength and shapeof the electric field formed between the anode and the cathode, therebyaltering the deposition of material onto the surface of themicroelectronic workpiece. Still further, consumable anodes erode to thepoint where they eventually need to be replaced.

[0013] Processes that do not make use of a consumable anode have alsobeen developed. Generally, in these processes an inert anode is used inplace of the consumable anode. Where the consumable anode, can provide asource for ions in the plating bath, an inert anode generally does notsupply ions to the plating bath. In processes that use an inert anode,ions in the plating bath are generally replenished from the flow offresh chemistry into the plating reactor. The plating solutioncontaining fresh chemistry generally displaces the plating solution fromwhich plating ions have been depleted. Consequently, the concentrationof plating ions within the plating bath is largely affected by the flowof fresh plating solution within the plating reactor.

[0014] However the flow of plating solution is seldom uniform. Theuniformity of the flow of fresh plating solution within the platingreactor can be affected by several different factors. One such factorincludes the size, shape and position of the fluid inlet and the fluidoutlet, which defines the starting point and the ending point for thefluid entering and or exiting the reactor. A further factor includes thesize, shape and position of elements within the plating reactor, whichmay limit or obstruct fluid flow within the plating reactor, therebyaltering the path of the fluid flow within the plating reactor. Forexample an object within the plating reaction may force fluid to bediverted around the object resulting in the fluid flow being morenarrowly channeled around the outer periphery of the object.Additionally, this may result in the creation of dead spots within thechamber around which the fluid has been diverted and where theprocessing fluid remains relatively stagnant. This can result inlocalized areas where replenishment of the processing fluid and thecorresponding concentration of fresh plating ions is affected therebyresulting in non-uniformity of the deposited film.

[0015] One factor that can affect the rate at which a material iselectroplated onto a workpiece is the concentration of the ion speciesproximate the surface of the workpiece. As ions are consumed or platedout of the plating solution proximate a particular location on thesurface of the workpiece, the ions need to be replaced or replenished toinsure ions are available for continued plating of the material onto thesurface of the workpiece. To the extent that the ions necessary forfurther plating are not replenished, the rate of reaction at the surfaceof the microelectronic workpiece will suffer. Local differences in therate of plating can result in undesirable non-uniformity of the overallplated layer.

[0016] Still further, a related electrochemical oxidation reaction takesplace proximate the inert anode. This related reaction similarlyrequires that certain ions be present and continuously replenished forthe related reaction to continue at the anode in the desirable manner.For example, in the absence of a suitable reducing agent proximate theanode, water in the plating bath may be oxidized resulting in gasbubbles at the anode. This may contaminate the processing bath andinterfere with the formation of the thin film layer at the surface ofthe microelectronic workpiece. Additionally, the related reaction at theanode may be impacted by local concentrations of ions in the platingsolution and the corresponding fluid flow proximate portions of theanode.

[0017] The present inventors have recognized the foregoing problems andhave developed a reactor for electrochemically processing amicroelectronic workpiece that manages the flow of electrochemicalprocessing solution within the reactor so as to provide for a generallyuniform flow of processing solution throughout. Flow of theelectrochemical processing solution is controlled proximate theworkpiece as well as proximate the anode. Such control provides for amore even distribution in the concentration of reactants required forthe electrochemical processing reactions at the anode and the cathode.In this way, uniform electrochemical processing, such as theelectrolytic deposition of material onto a microelectronic workpiece,can be achieved.

BRIEF SUMMARY OF THE INVENTION

[0018] A reactor assembly for electrochemically processing amicroelectronic workpiece is set forth. The reactor assembly includes aprocessing bowl having one or more fluid inlets through which a flow ofprocessing fluid is received. An electrode assembly is located withinthe process bowl in a fluid flow path of the fluid provided through theone or more fluid inlets. The electrode assembly includes a meshelectrode and a diffuser disposed in the fluid flow path prior to themesh electrode to tailor the flow of processing fluid received from theone or more fluid inlets through the mesh electrode in a predeterminedmanner.

[0019] In accordance with one embodiment of the invention, the diffuseris formed as a separate component from the mesh electrode. The diffuseris disposed between the one or more fluid inlets and the mesh electrodeto tailor the flow of processing fluid traveling between the one or morefluid inlets and the mesh electrode. In accordance with anotherembodiment the diffuser is integral with the mesh electrode. The reactormay also include an electrode support assembly that is dimensioned todirect substantially all of the processing fluid received through theone or more fluid inlets toward the mesh electrode.

[0020] A further diffuser may also be employed between a portion of thefluid flow path between the mesh electrode and the microelectronicworkpiece. Optionally, the further diffuser may be constructed so thatthe flow therethrough optimizes the conditions under which the fluidcontact the mesh electrode. This assists in ensuring that the fluid andmesh anode are in contact with one another under conditions that allowthe completion of any reactions between them before the fluid isprovided for contact with contact the microelectronic workpiece beingprocessed. Alternatively, or in addition, a pump that is used to supplythe fluid to the reactor chamber may control such flow.

[0021] Various constructions of the mesh electrode are also set forth.Further, an integrated tool including a reactor constructed inaccordance with one embodiment of the present invention is set forth.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0022]FIG. 1 is a cross-sectional side view of a reactor assemblyconstructed in accordance with one embodiment of the present invention.

[0023]FIG. 2 is an isometric view of one example of an electrode for usein the reactor assembly illustrated in FIG. 1 viewed from the bottom.

[0024]FIG. 3 is a partial plan view showing one manner in which a firstlayer of wire mesh forming the electrode illustrated in FIG. 2 may beoriented.

[0025]FIG. 4 is a partial plan view showing one manner in which a secondlayer of wire mesh forming the electrode illustrated in FIG. 2 may beoriented.

[0026]FIG. 5 is a partial plan view of the electrode illustrated in FIG.2 showing one manner in which the first layer of wire mesh materialillustrated in FIG. 3 may be combined with the second layer of wire meshmaterial illustrated in FIG. 4.

[0027]FIG. 6 is an isometric view of a further example of an electrodefor use in the reactor assembly illustrated in FIG. 1 viewed from thebottom.

[0028]FIG. 7 is an exploded isometric view showing a portion of theelectrode assembly illustrated in FIG. 1 as viewed from the bottom.

[0029]FIG. 8 is an isometric view of the portion of the electrodeassembly illustrated in FIG. 7.

[0030]FIG. 9 is a top isometric view of the portion of the electrodeassembly illustrated in FIG. 8.

[0031]FIG. 10 is a top plan view of the embodiment of the reactor shownin FIG. 1 in which the head assembly has been removed.

[0032]FIG. 11 is an isometric view of an integrated processing tool inaccordance with one embodiment of the present invention in which theprocessing tool is shown with several panels removed.

[0033]FIG. 12 is a further isometric view of the integrated processingtool shown in FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION

[0034]FIG. 1 is a cross-sectional side view of a reactor assembly 30 forelectrochemically processing a microelectronic workpiece in accordancewith one embodiment of the present invention. In the particularembodiment of the invention shown here, the reactor 30 is adapted forelectrochemical deposition of a metal, such as copper or a copper alloy,onto the surface of the microelectronic workpiece. Accordingly, thefollowing description includes express references to elements used insuch electrochemical deposition processes. It will be recognized,however, that the architecture of the reactor 30 is suitable for a widerange of electrochemical processing operations including, for example,anodization, electro-etch, electropolishing, etc. of a surface of theworkpiece.

[0035] The reactor 30 has a head assembly 32 that assists in supportingthe workpiece during processing, and a corresponding processing space inthe form of a bowl assembly 34. The bowl assembly 34 includes one ormore walls that define a processing space that receives a processingfluid, as will be set forth in further detail below. This type ofreactor 30 is particularly suited for effecting electroplating ofsemiconductor waters or like workpieces, in which the workpiece iselectroplated with a blanket or patterned metallic layer.

[0036] The head assembly 32 and the bowl assembly 34 of the illustratedembodiment may be moved relative to one another. For example, a lift androtate mechanism, not shown, may be used in conjunction with the headassembly 32 and the bowl assembly 34 to drive the head assembly 32 in avertical direction with respect to the bowl assembly 34 and to rotatethe head assembly 32 about a horizontally disposed axis. By lifting androtating the head assembly 32, a workpiece 36, such as a semiconductorwafer, may be moved between a load position that allows the workpiece 36to be placed upon the head assembly 32, and a processing position inwhich at least a portion of the workpiece 36 is brought into contactwith processing fluid in the processing space of the bowl assembly 34.When the workpiece 36 is in the processing position, it is generallyoriented with the process side down within the processing space. Whenthe workpiece 36 is in the load position, the workpiece 36 is generallyexposed outside of the bowl assembly 34 with the process side directedupward, for loading and unloading by, for example, a workpiece transportunit 18. One example of a suitable lift and rotate mechanism isdescribed in connection with U.S. patent application Ser. No.09/351,980, filed Jul. 12, 1999, entitled “Lift and Rotate Mechanism forUse in a Workpiece Processing Apparatus”, the disclosure of which isincorporated herein by reference.

[0037] The head assembly 32 may include a stationary section 38 and arotational section 40. The rotational section 40 is coupled to thestationary section 38 via a motor 42. The rotational section 40 isconfigured with one or more structures that serve to support theworkpiece and to rotate the workpiece 36 about a generally vertical axisduring, for example, workpiece processing.

[0038] In the reactor assembly embodiment 30 of FIG. 1, the workpiece 36is held in place, with respect to the rotational section 40 by contactassembly 44. In addition to holding the workpiece 36 in place, thecontact assembly 44 may include one or more electrical contacts that aredisposed to engage the workpiece 36 for applying electrical power usedin the electrochemical processing operation. One embodiment of a contactassembly is described in detail in connection with U.S. patentapplication Ser. No. 09/386,803, filed Aug. 31, 1999, entitled “Methodand Apparatus for Processing the Surface of a MicroelectronicWorkpiece”, the disclosure of which is incorporated herein by reference.It will be recognized, however, that other contact architectures, suchas discrete finger contacts or the like, are also suitable depending onthe desired electrochemical processing that is to take place in thereactor 30. An alternative contact configuration including a J-hookdesign is described in connection with U.S. patent application Ser. No.08/680,057, filed Jul. 15, 1996, and entitled “Electrode SemiconductorWorkpiece Holder”, the disclosure of which is similarly incorporatedherein by reference.

[0039] During processing, the workpiece 36 is brought into contact withprocessing fluid located within the bowl assembly 34. In the illustratedembodiment, bowl assembly 34 comprises a processing base 46 that, inturn, includes processing bowl 48. The processing bowl 48 has an outerwall, which defines a processing space into which a flow of theprocessing fluid is provided. An electrode assembly 50 constructed inaccordance with one embodiment of the present invention is disposedwithin the processing bowl 48. The electrode assembly 50 includes anelectrode 52 that is in electrical contact with the processing fluidlocated within the processing space. Electrode 52, as will be set forthin further detail below, is used in the electrochemical processing ofworkpiece 36.

[0040] Electrode 52 is constructed to allow processing fluid to passthrough it. For example, electrode 52 may be formed from a conductivematerial that has been woven into a mesh structure having apredetermined fluid flow permeability suitable for the particularprocess and the desired control of the flow of electrochemicalprocessing solution. In the illustrated embodiment, the electrode 52 isformed from one or more layers of wire mesh material that allow theprocessing fluid to flow through the interstitial regions formed betweenthe woven material. Although other materials may be used to form theelectrode 52, the wire mesh material may be formed from an inertmaterial, such as platinized titanium. Other examples of suitablematerials for forming the electrode 52 include iridium oxide, ruthenium,palladium, ceramic, and metal oxide. By using a wire mesh, the flow ofprocessing fluid can proceed past the electrode 52 with minimaldisruption to the uniformity of the fluid flow. The electrode 52 mayalso be formed, at least in part, from a consumable material.

[0041] In addition to providing minimal disruption of the uniformity ofthe fluid flow as the processing fluid proceeds past the electrode 52,by flowing through the electrode 52 as opposed to around the electrode52, stagnant fluid flow areas in the processing bowl 48 proximate thesurface of the electrode 52 are generally avoided. In this way freshchemistry including replenishing levels of reactive ions is adequatelysupplied proximate the electrode 52.

[0042]FIG. 2 is a bottom isometric view of one embodiment of anelectrode 52 and appertaining structures that may be used in reactor 30illustrated in FIG. 1. As shown, a connector 54 may be provided at thebase of electrode 52 for supplying electrical power to the electrode.The specific function of the electrode during electrochemical processingis, of course, dependent upon the specific type of electrochemicalprocessing that is being executed. For example, in electroplating ametal or a metal alloy onto the surface of the microelectronicworkpiece, the electrode 52 is connected to an external electrical powersupply so that it functions as an anode. In other electrochemicalprocesses, such as anodization, de-plating, etc., the electrode 52 isconnected to function as a cathode.

[0043] A pair of standoffs 53 may be provided for connecting theelectrode 52 to other elements of the electrode assembly 50. This isdiscussed below in greater detail in connection with FIGS. 7-9.

[0044] As noted above, electrode 52 may be formed from multiple layersof overlaid wire mesh material. Such a construction is illustrated inFIGS. 3-5. In this construction, the layers may be rotated with respectto one another, so as to retain the overall porous nature of theelectrode 52, while concurrently reducing the size of the openings inthe electrode 52 through which the processing fluid flows. FIGS. 3 and 4are partial plan views of single material layers that may be joined toform such a multiple layer electrode configuration. In the illustratedembodiment, a dual layer structure is employed. The dual layer structureincludes a first layer 55 and a second layer 56, each formed from a wiremesh having the exemplary angular orientation of wire material shown inFIGS. 3 and 4, respectively. FIG. 5 is a partial plan view of electrode52 showing the first wire mesh layer 55 overlying the second wire meshlayer 56 to form the composite electrode 52.

[0045] In the illustrated embodiment, connector 54 may be soldered toelectrode 52, proximate the center of electrode 52. With reference toFIG. 1, the connector 54 may be of the type that mates with acorresponding connector 57, such as a banana plug or the like, locatedproximate the center of the base of the processing bowl 48. Such aconnector configuration facilitates simple connector alignment, therebymaking it an easy task to connect and remove the electrode assembly 50to and from the processing bowl 48.

[0046] This connector configuration, however, may result in anobstruction to fluid flow through the center of electrode 52 and affectprocessing of the workpiece at one or more sites corresponding to theobstructive fluid flow path. Even if the microelectronic workpiece 36 isrotated during processing, the same portion of the microelectronicworkpiece 36 will generally remain above the obstructive fluid flow pathwhen the axis of rotation for the microelectronic workpiece 36 coincideswith the position of the mating connectors.

[0047] Alternatively, the position of the mating connectors may belaterally offset from center. With such an offset connectorconfiguration, however, greater care must generally be used in aligningthe mating connectors 54, 57. This laterally offset configuration may beused to position the fluid flow path obstruction beneath a non-centralportion of the microelectronic workpiece 36 corresponding to the lateraloffset of the position of the mating connectors. By using such an offsetposition, the time any given portion of the microelectronic workpiece 36is disposed along the obstructive fluid flow path is generally limited.Nevertheless, asymmetrical processing will occur radially across thesurface of the workpiece due to the obstructive fluid flow path.

[0048] As a further alternative, the position of the mating connectorcould remain aligned with the center of the electrode 52, but bevertically offset. An example of an embodiment incorporating thisfurther alternative is illustrated in FIG. 6. In FIG. 6, a connector 61is illustrated soldered to electrode 63. In the illustrated embodiment,connector 61 is soldered to electrode 63 via three legs 73, which extendfrom the base 71 of the connector 61. In addition to elevating the bulkof the connector away from the surface of the electrode 63, the legs 73also laterally offset the three points of electrical contact away fromthe center of the electrode 63. This enables the points of electricalcontact to be aligned below different portions of the workpiece 36 asthe workpiece 36 is rotated with respect to the electrode 61. Otherwisethe electrode 61 is similar to the electrode 52 illustrated in FIG. 2.

[0049] In addition to the fluid flow management properties of the porouselectrode 52, other portions of the electrode housing assembly 50 alsocontribute to the overall fluid flow management. Such portions includean electrode support assembly 58 having a plurality of openings 60through which processing fluid can flow. The support assembly 58 has anouter circumference that may extend to and engage the inner wall of theprocessing bowl 48. By extending the outer circumference of the supportassembly 58 to the inner wall of the processing bowl 48, the processingfluid is substantially prevented from flowing around the outercircumference of the support assembly 58. As a result, the flow ofprocessing fluid is principally limited to the plurality of openings 60.The plurality of openings 60 of the support assembly 58 may bepositioned to evenly distribute the flow of processing fluid or tootherwise tailor the fluid flow in a manner that is optimized for theparticular process that is implemented. In the absence of the supportassembly 58, the fluid would tend to travel upward along the outer wallof the processing bowl 48. By incorporating the support assembly 58, theflow of processing fluid is at least partially diverted back towards thecenter of the processing bowl 48 so that it may flow in the desiredmanner through the electrode 52.

[0050] The electrode housing assembly 50 may also include a pair ofdiffusers, a lower diffuser 62 and an upper diffuser 64, that contributeto the fluid flow management. Similar to support assembly 58, each ofthe diffusers 62 and 64 includes a corresponding plurality of openingsthrough which the processing fluid is diverted. The fluid travelsthrough the respective diffuser 62, 64 via the plurality of openings.The size, shape and location of the plurality of openings through eachof the diffusers 62, 64 help define the resulting fluid distribution. Inorder to more precisely control and/or manually adjust the flow of fluidthrough each of the diffusers, the individual openings can be manuallycovered and/or uncovered by using, for example, plugs in the individualopenings.

[0051] The lower diffuser 62 of the illustrated embodiment is orientedin a plane substantially parallel to the electrode 52, and is locatedbetween the electrode 52 and the support assembly 58. Since lowerdiffuser 62 is positioned before the electrode 52 in the fluid flowpath, the flow of the processing fluid prior to contacting the electrode52 is modified. Specifically, the lower diffuser 62 may be designed tosubstantially distribute the flow of fluid evenly across the entiresurface of the electrode 52. As the fluid flows through the electrode 52in this manner, fluid containing fresh chemistry replaces the fluidpreviously proximate the electrode 52. In this way fresh reactants canbe continuously supplied across substantially the entire surface of theelectrode 52, thereby inhibiting the formation of fluid stagnation areasthat may adversely impact the overall electrochemical process. Inaddition to the openings through which the processing fluid flows, thelower diffuser 62 and the support assembly 58 may also include one ormore openings through which the electrical connection is made to theelectrode 52. In some instances, lower diffuser 62 may be used without asupport assembly 58. In such instances, it may be desirable to extendthe circumference of lower diffuser 62 to the inner walls of theprocessing bowl so that substantially all of the fluid proceeding fromfluid inlet 68 is directed through the openings of diffuser 62.Alternatively, in other instances, a support assembly 58 may be usedwithout a lower diffuser 62.

[0052] The upper diffuser 64 of the illustrated embodiment is alsooriented in a plane substantially parallel to the electrode 52. Howeveras opposed to being located between the electrode 52 and the supportassembly 58, the upper diffuser 64 is located between the electrode 52and the microelectronic workpiece 36 (or between the electrode 52 andother electrical/fluid flow management devices). This allows the flow ofprocessing fluid to be principally constrained to a flow region tailoredto the specific shape of microelectronic workpiece 36 or to otherwisemeet processing parameters defined by the processing recipe. This fluidflow management configuration thus allows the fluid flow throughelectrode 52 to be optimized by lower diffuser 62 in accordance with oneset of predetermined fluid flow characteristics while concurrentlyallowing the electrochemical processing fluid flow to, for example, themicroelectronic workpiece 36 is provided in accordance with a furtherset of predetermined fluid flow characteristics. For example, it may bedesirable to localize the flow of processing fluid to the area of theelectrode 52 using lower diffuser 62 and to provide a more diffuse flowof processing fluid to the surface of the microelectronic workpiece 36using upper diffuser 64. As a result of the tailored fluid flows, theelectrochemical reactions at the electrode 52 and at the surface of themicroelectronic workpiece 36 may be optimized to provide substantiallyuniform electrochemical processing of the workpiece.

[0053] In an alternative embodiment, the upper diffuser 64 may beconstructed to cooperate with the design of the lower diffuser 62 (or,alternatively, be self-sufficient) to optimize the time duration overwhich the fluid and mesh electrode are in contact with one another. Aswill be recognized, such optimization can be achieved through theparticular placement of the openings in each of the diffusers and/orusing the relative overall flow areas defined by the openings of thediffusers as a diffuser design constraint. This may, if desired, be usedto assist in ensuring that the fluid and mesh anode are in contact withone another under conditions that allow the completion of any reactionsbetween them before the fluid is allowed to contact and react with themicroelectronic workpiece.

[0054] In some instances it may be possible to incorporate thefunctionality of one or both of the diffusers 62, 64 into the structureof the electrode 52. To this end, the mesh electrode 52 have amultilayer structure in which the openings defined by a mesh structureat the upper and lower surfaces of the electrode provide the tailoredfluid flow. Furthermore, such effects can be localized with respect tocertain portions of the electrode 52 or can be made more uniform acrossthe entire surface of the electrode 52 by adjusting the specificconstruction of the electrode 52. In these instances, the use of both anupper diffuser 64 and a lower diffuser 62, as well as the fluiddistribution capabilities of the support assembly 58 may not be needed,but may be optionally included in the overall assembly.

[0055]FIG. 7 is an exploded isometric view showing the support assembly58, the lower diffuser 62 and the electrode 52 of the electrode assembly50. The support assembly 58, the lower diffuser 62 and the electrode 52,in the illustrated embodiment may be at least partially held together bythreaded fasteners 65 or the like. A first pair of threaded fasteners 65connects the support assembly 58 to the lower diffuser 62 throughcorresponding threaded holes 66 in the lower diffuser 62. A second pairof threaded fasteners connects the support assembly 58 to standoffs 53of the electrode 52 through a pair of aligned openings 67 in the lowerdiffuser 62. The support assembly 58 further includes four clips 69located around the outer circumference of the support assembly 58 tofacilitate insertion of the electrode assembly 50 into the processingbowl 48. FIGS. 8 and 9 are top and bottom isometric view of theassembled electrode assembly 50.

[0056]FIG. 10 it is a top plan view of the reactor 30 with the headassembly 32 removed. In connection therewith, FIG. 10 furtherillustrates one potential hole pattern of the top diffuser 64 that maybe used to tailor the fluid flow to the microelectronic workpiece.

[0057] With reference again to FIG. 1, a fluid inlet 68 is disposed atthe bottom of the processing bowl 48 and includes one or more openingsthat are in fluid communication with a riser tube 70, through whichprocessing fluid is received. The processing fluid is generally receivedfrom a fluid reservoir located external to the reactor 30.

[0058] The processing fluid is directed through the riser tube 70 intothe processing bowl 48 via the fluid inlet 68. The processing fluid thenenters the electrode assembly 50 via the plurality of openings 60 in thesupport assembly 58. As the fluid passes through the support assembly 58via the plurality of openings 60, the distribution of the flow ofprocessing fluid is tailored so that it is at least partially divertedtoward the center of the processing bowl 48 away from the outer wall.After passing through the openings 60 of the support assembly 58 thefluid flows through the lower diffusor 62, where the fluid flow istailored, at least in the illustrated embodiment, to maximize fluid flowthrough and fluid contact with the conductive portions of electrode 52.

[0059] Once the processing fluid has passed through the electrode 52, itencounters the upper diffuser 64. As fluid flows through this upperdiffuser, the flow is again tailored so that it may be evenlydistributed across the surface of the microelectronic workpiece 36, orhas such other characteristics desirable for the particular processingrecipe that is being implemented. Further, as noted above, the upperdiffuser 64 may be constructed to cooperate with the design of the lowerdiffuser 62 to optimize the conditions under which the fluid and meshelectrode are in contact with one another. This assists in ensuring thatthe fluid and mesh anode are in contact with one another underconditions that allow the completion of any reactions between thembefore the fluid is allowed to contact and react with themicroelectronic workpiece. After contacting the microelectronicworkpiece 36, the fluid exits from the processing cup over an overflowweir 72, shown here as the upper lip of the processing bowl 48. Arrowsillustrate examples of partial fluid flows as the processing fluidprogresses through the processing bowl 48.

[0060] It will be recognized that the foregoing reactor 30 may beemployed in any number of microelectronic fabrication environmentsrequiring the electrochemical processing of one or more microelectronicworkpieces. For example, as illustrated in FIGS. 11 and 12, the reactor30 may be disposed in an integrated processing tool 100 or the like.

[0061]FIGS. 11 and 12 illustrate corresponding isometric views of oneexample of such an integrated processing tool 100. The integratedprocessing tool 100 is shown with several panels removed. The integratedprocessing tool 100 incorporates multiple processing stations 102 of thesame and/or varying types. Workpieces are generally received within theintegrated processing tool 100, via one or more cassettes containing oneor more workpieces. The cassettes containing the workpieces enter andexit the integrated processing tool 100, via a door in the side of theintegrated processing tool 100, where the cassettes are received by apair of lift/tilt mechanisms 104. The lift/tilt mechanisms 104 positionand orient the cassettes to provide access to the individual workpiecescontained therein. A linear conveyor system 106 receives the individualworkpieces and relays them to the various processing stations 102.

[0062] Additional details in connection with at least one example of alift/tilt mechanism 104 and a linear conveyor system 106 are provided inconnection with U.S. patent application Ser. No. 08/990,107, entitled“Semiconductor Processing Apparatus having Linear Conveyor System”, thedisclosure of which is incorporated herein by reference.

[0063] In accordance with one embodiment, the linear conveyor system 106includes two workpiece transport units 108 or robot arms, which moveindependently with respect to one another. One of the workpiecetransport units 108 generally handles dry workpieces, while the otherworkpiece transport unit 108 generally handles wet workpieces.

[0064] The illustrated integrated processing tool 100 may also include apre-aligner 110, which establishes the alignment of the workpiece withinthe integrated processing tool 100 by referencing a known registrationnotch on each of the workpieces. Prior to forwarding the workpiece toany of the other processing stations 102, the workpiece may be placedwithin the pre-aligner 110 to locate the registration notch. After thepre-aligner 110 locates the registration notch, the pre-aligner 110 thenmakes any necessary adjustments to the orientation and alignment of theworkpiece for facilitating proper subsequent handling. The integratedprocessing tool 100 can incorporate any one of several knownpre-aligners commonly available. An example of one such suitablepre-aligner for use in the integrated processing tool 100, as presentlyconfigured, includes a prealigner manufactured and sold by PRIAutomation, Equipe Division, under the model number PRE-201-CE.

[0065] The integrated processing tool 100 can further include variouscombinations and arrangements of individual processing stations 102. Inaddition to reactor 30 described above in connection with FIGS. 1-10,other examples of the various types of processing stations 102 for usein the integrated processing tool 100 could include SRD modules (Spin,Rinse, Dry), pre-plate modules, magnetic reactor processing stations,and/or non-magnetic reactor processing stations.

[0066] By integrating reactor 30 into an integrated processing tool 100including additional processing stations 102, several processing stepscan be performed with respect to a workpiece while correspondinglyreducing the amount of intervening handling required by an operator.

[0067] Numerous modifications may be made to the foregoing systemwithout departing from the basic teachings thereof. Although the presentinvention has been described in substantial detail with reference to oneor more specific embodiments, those of skill in the art will recognizethat changes may be made thereto without departing from the scope andspirit of the invention as set forth in the appended claims.

What is claimed is:
 1. A reactor for processing a microelectronicworkpiece comprising: a processing bowl having one or more fluid inletsthrough which a flow of processing fluid is received; and an electrodeassembly located within the process bowl in a fluid flow path of thefluid received through the one or more fluid inlets, the electrodeassembly comprising a mesh electrode through which processing fluid mayflow, and a diffuser disposed in the fluid flow path prior to the meshelectrode to tailor the flow of processing fluid received from the oneor more fluid inlets through the mesh electrode in a predeterminedmanner.
 2. A reactor in accordance with claim 1 and further comprising afurther diffuser disposed between the mesh electrode and the workpieceto tailor the flow of the processing fluid traveling between the meshelectrode and the workpiece.
 3. A reactor in accordance with claim 1 andfurther comprising a support assembly that is dimensioned to directsubstantially all of the processing fluid received through the fluidinlet to flow through the diffuser toward the mesh electrode.
 4. Areactor in accordance with claim 1 wherein the reactor further comprisesa head assembly adapted to receive a microelectronic workpiece and toconduct electrical power to the microelectronic workpiece.
 5. A reactorin accordance with claim 4 wherein the head assembly is movable from aworkpiece loading position to a workpiece processing position in whichthe workpiece is in contact with the flow of processing fluid.
 6. Areactor in accordance with claim 4 wherein the head assembly includes arotor and a rotor drive connected to rotate the microelectronicworkpiece with respect to the bowl assembly during electrochemicalprocessing.
 7. A reactor in accordance with claim 1 wherein theelectrode assembly further comprises a support assembly having an outercircumference which extends proximate to an internal surface of theprocessing bowl to thereby direct a substantial portion of the fluidproceeding from the one or more fluid inlets toward the mesh electrode.8. A reactor in accordance with claim 1 wherein the mesh electrodecomprises a plurality of mesh layers.
 9. A reactor in accordance withclaim 8 wherein the plurality of mesh layers are offset from one anotherto define interstitial regions through which the processing fluid mayflow.
 10. A reactor in accordance with claim 1 wherein the electrodeassembly further comprises a connector coupled to the mesh electrodethrough which processing power is supplied to the mesh electrode.
 11. Areactor in accordance with claim 10 wherein the connector is soldered tothe mesh electrode.
 12. A reactor in accordance with claim 10 whereinthe connector is centered with respect to the mesh electrode.
 13. Areactor in accordance with claim 10 wherein the connector is offset fromthe center of the mesh electrode.
 14. A reactor in accordance with claim10 wherein the connector is coupled to the mesh electrode by a standoff.15. A reactor in accordance with claim 14 wherein the standoff includesa base connected to the mesh electrode via a plurality of legs.
 16. Areactor in accordance with claim 0 wherein the mesh electrode iscomprised of an inert material.
 17. A reactor in accordance with claim16 wherein the mesh electrode is comprised of platinized titanium.
 18. Amicroelectronic workpiece processing apparatus comprising: aninput/output section adapted for loading and unloading groups ofmicroelectronic workpieces; a processing section having one or moreprocessing stations for processing the microelectronic workpieces, atleast one of the processing stations comprising a reactor assemblyincluding a processing bowl having one or more fluid inlets throughwhich a flow of processing fluid is received, an electrode assemblylocated within the process bowl in a fluid flow path of the fluidreceived through the one or more fluid inlets, the electrode assemblyincluding a mesh electrode through which processing fluid may flow, anda diffuser disposed in the fluid flow path prior to the mesh electrodeto tailor the flow of processing fluid received from the one or morefluid inlets through the mesh electrode in a predetermined manner, and amicroelectronic workpiece transfer apparatus disposed to convey themicroelectronic workpieces between at least the input/output section andthe one or more processing stations.
 19. A microelectronic workpieceprocessing apparatus in accordance with claim 18 and further comprisinga further diffuser disposed between the mesh electrode and the workpieceto tailor the flow path of the processing fluid traveling between themesh electrode and the workpiece.
 20. A microelectronic workpieceprocessing apparatus in accordance with claim 18 wherein the electrodeassembly further comprises a support assembly that is dimensioned todirect substantially all of the processing fluid received through theone or more fluid inlets to flow through the diffuser.
 21. Amicroelectronic workpiece processing apparatus in accordance with claim18 wherein the reactor assembly includes a head assembly adapted forreceiving a microelectronic workpiece and conducting electrical power tothe microelectronic workpiece.
 22. A microelectronic workpieceprocessing apparatus in accordance with claim 21 wherein the headassembly is movable to bring the workpiece into contact with the flow ofprocessing fluid in the process bowl.
 23. A microelectronic workpieceprocessing apparatus in accordance with claim 21 wherein the headassembly includes a rotor and a rotor drive connected to rotate themicroelectronic workpiece with respect to the processing bowl duringelectrochemical processing.
 24. A microelectronic workpiece processingapparatus accordance with claim 18 wherein the electrode assemblycomprises a support assembly having an outer circumference which extendsproximate to an internal surface of the processing bowl.
 25. Amicroelectronic workpiece processing apparatus in accordance with claim21 wherein the mesh electrode comprises a plurality of mesh layers. 26.A microelectronic workpiece processing apparatus in accordance withclaim 25 wherein the plurality of mesh layers are offset from oneanother to define interstitial regions through which the processingfluid may flow.
 27. A microelectronic workpiece processing apparatus inaccordance with claim 18 wherein the electrode assembly furthercomprises a connector coupled to the mesh electrode through whichprocessing power is supplied to the mesh electrode.
 28. Amicroelectronic workpiece processing apparatus in accordance with claim27 wherein the connector is soldered to the mesh electrode.
 29. Amicroelectronic workpiece processing apparatus in accordance with claim27 wherein the connector is centered with respect to the mesh electrode.30. A microelectronic workpiece processing apparatus in accordance withclaim 27 wherein the connector is offset from the center of the meshelectrode.
 31. A microelectronic workpiece processing apparatus inaccordance with claim 27 wherein the connector is coupled to the meshelectrode by a standoff.
 32. A microelectronic workpiece processingapparatus in accordance with claim 31 wherein the standoff includes abase connected to the mesh electrode via a plurality of legs.
 33. Amicroelectronic workpiece processing apparatus in accordance with claim18 wherein the mesh electrode is comprised of an inert material.
 34. Amicroelectronic workpiece processing apparatus in accordance with claim18 wherein the mesh electrode is comprised of platinized titanium. 35.An electrode assembly for use in processing a microelectronic workpiececomprising: a mesh electrode through which processing fluid may flow,and a diffuser disposed proximate to the mesh electrode to tailor theflow of processing fluid flowing to the mesh electrode in apredetermined manner.
 36. An electrode assembly in accordance with claim35 and further comprising an additional diffuser located proximate themesh electrode so as to tailor the flow of processing fluid flowing fromthe mesh electrode.
 37. An electrode assembly in accordance with claim34 and further comprising a support assembly coupled to the meshelectrode, wherein the support assembly is dimensioned to directsubstantially all of the processing fluid toward the mesh electrode andthereby limiting the amount of processing fluid flowing around the meshelectrode toward a microelectronic workpiece being processed.
 38. Anelectrode assembly in accordance with claim 35 wherein the meshelectrode comprises a plurality of mesh layers.
 39. An electrodeassembly in accordance with claim 37 wherein the plurality of meshlayers are offset from one another to define interstitial regionsthrough which the processing fluid may flow.
 40. An electrode assemblyin accordance with claim 35 wherein the electrode assembly furthercomprises a connector coupled to the mesh electrode through whichprocessing power is supplied to the mesh electrode.
 41. An electrodeassembly in accordance with claim 40 wherein the connector is solderedto the mesh electrode.
 42. An electrode assembly in accordance withclaim 39 wherein the connector is centered with respect to the meshelectrode.
 43. An electrode assembly in accordance with claim 40 whereinthe connector is offset from the center of the mesh electrode.
 44. Anelectrode assembly in accordance with claim 40 wherein the connector iscoupled to the mesh electrode by a standoff.
 45. An electrode assemblyin accordance with claim 44 wherein the standoff includes a baseconnected to the mesh electrode via a plurality of legs.
 46. Anelectrode assembly in accordance with claim 35 wherein the meshelectrode is comprised of an inert material.
 47. An electrode assemblyin accordance with claim 46 wherein the mesh electrode is comprised ofplatinized titanium.
 48. A reactor for processing a microelectronicworkpiece comprising: a processing bowl having one or more fluid inletsthrough which a flow of processing fluid is received; and an electrodeassembly located within the process bowl in a fluid flow path of thefluid received through the one or more fluid inlets, the electrodeassembly comprising a mesh electrode through which processing fluid mayflow, and a diffuser disposed in the fluid flow path proximate an outletside of the mesh electrode to assist in optimizing the conditions underwhich processing fluid is in contact with the mesh electrode.